Chemotherapy Basics for Breast Cancer

woman receiving chemotherapy treatment
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Nancy had chemotherapy in the early 1980s for the recurrence of her breast cancer. Back then, chemo treatments were given in larger doses than they are now, and less was known about preventing side effects. She became quite ill and weak during treatment, and one of the drugs caused her to temporarily become color blind. Twenty years later, when I took chemo, doses were smaller and pre-medications were given to head off the worst side effects. Chemotherapy treatments for breast cancer have improved greatly, and survival rates are improving.

In order to help you understand the basics about chemotherapy, how it might affect you and your treatment decisions, I looked up what the experts say in UpToDate — a trusted electronic reference that is used by many of the oncologists who treat breast cancer patients.

You may or may not need chemotherapy. But you will need to know if chemotherapy will benefit you by improving your chances of survival. Start by reading this excerpt to see why chemotherapy may be important for you.

According to UpToDate, chemotherapy refers to the use of medicines to stop or slow the growth of ​cancer cells. Chemotherapy works by interfering with the ability of rapidly growing cells (like cancer cells) to divide or multiply. Because most of an adult's normal cells are not actively dividing or multiplying, they are not affected by chemotherapy. However, the bone marrow (where the blood cells are produced), the hair follicles, and the lining of the gastrointestinal (GI) tract are all growing. The side effects of chemotherapy drugs are related to effects on these and other normal tissues.

What Is Chemotherapy?

Chemotherapy can be defined as the therapeutic use of chemicals to treat or control a disease. Chemotherapy for breast cancer is a systemic treatment, which affects most of the cells in your body. These powerful drugs are used to kill or delay the growth of cancer cells by disrupting their DNA, protein production, preventing cell division, starving them of nutrients, or blocking hormone receptors.

What Drugs Are Used For Breast Cancer?

Many drugs and regimens fight breast cancer. Here are some of the drug combinations:

  • CMF: Cytoxan (cyclophosphamide), methotrexate, and 5-FU (5-fluorouracil)
  • AC: Adriamycin (doxorubicin) and Cytoxan
  • CAF or FAC: Cytoxan, Adriamycin, and 5-FU
  • CEF or FEC: Cytoxan, Ellence (epirubicin), and 5-FU
  • TC: Taxotere (docetaxel) and Cytoxan

Additional Drugs to Treat Cancer

Some diagnoses will require the addition of other drugs, to target specific proteins or reduce the flow of blood and nutrients to the tumor.

For people who have estrogen receptor positive breast cancer, options include tamoxifen or one of the aromatase inhibitors.

For those who have tumors that are HER2 positive, HER2 targeted therapies such as Herceptin, Tykerb (lapatinib), Perjeta, and TDM-1 may be used.

How Are Chemotherapy Treatments Given?

Many chemotherapy drugs for breast cancer are given in a fluid form, as intravenous infusions, or injections, but are also available as pills or tablets. Some drugs may be given alone, and other drugs are combined to work together. When chemo drugs are given in combination, the treatment is called a regimen. Intravenous chemotherapy is given in infusions of 7- to 21-day cycles.

Typically, chemo is given once every three weeks, and you will need the intervening time to recover your blood counts and allow the drugs to work. Low-dose chemo is given weekly, as a smaller dose of drugs will require less recovery time. Oral chemo can be taken daily, or as directed. Injections may be given before, during, or after a chemo infusion.

Why Chemotherapy Causes Side Effects

The powerful nature of chemo treatment is both its strength and the reason behind its bad reputation in regards to side effects. Chemo targets rapidly growing cells such as cancer. It may also affect your naturally fast-growing cells such as blood, mucous tissue in your digestive tract, finger and toenails, and hair follicles. These effects will subside after you've finished treatment.

How Can I Get Help Coping With Treatments?

Before each chemo infusion, you will be given medications to prevent nausea and vomiting. These may be pills, others may be fluids that are injected into your intravenous drip. After your infusion, you may need to take anti-nausea medications, so be sure to get that prescription filled before your treatment. You may also be given anti-allergenic medications, or other substances to protect your healthy tissues. Be sure to let your doctor and nurses know what side effects you're having, and how severe those are. Ask for help managing the side effects. In most cases, the symptoms can be reduced or prevented.

Breast Cancer Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Woman

Chemotherapy Affects Your Present and Future Fertility

If you are premenopausal before starting treatment, be aware that chemo can put you into temporary or permanent menopause. Your periods may stop, and you could experience medical menopause, which may be temporary or permanent. Specific chemo drugs are known to cause infertility.

If you have any thoughts about future pregnancies, let your oncologist know before you start treatment. Ask what your options are if you're planning to add to your family. Depending on your age, drug regimen, and dosage, your fertility may return after treatment. But if there is a chance that you will become infertile, you need to know before your first chemo infusion.

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